Coil winding



IndenZor Aug. 27, 1929. R. c. DA COSTA COIL WINDING Filed May 24. 1928 Patented Aug. 27, 1929.

1,726,100 F I CE ROBERT C. DACOSTA, OF PHILADELPHIA,

PENNSYLVANIA, ASSIGNOR '10 A'IWATER KENT MANUFACTURING COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A COR- PORATION OF PENNSYLVANIA.

COIL WINDING.

Application filed May 24,

My invention relates to coil; windings, particularly such as are utilized in transformers adapted, for example, to supply energy to the electrode circuits of thermionic tubes of radio receiving apparatus.

In accordance with my invention, the ends of or terminals from one or more coil windings, as of a transformer, are freed of im sulating material, for example, of an enamel coating, in a suitable manner, preferably by deforming, specifically flattening, the ends of the conductor forming the inding, and during impregnation of the coil, particularly when mounted on the core structure, the bare ends of terminals, preferably suitably secured to the outside of the winding, as by tape, are coated with the impregnating mixture or compound, a resin or equivalent component of which serves as a fluxing agent facilitating attachment of leads by soldering to the coil ends; more particularly and preferably, the solder cooperates with apertures in the tape to prevent displacement of the leads.

My invention further resides in the method of construction and apparatus hereinafter described and claimed.

For an understanding of my invention, reference is to be had to the accompanying drawing, in which:

Figs. 1, 2 and 3 disclose a coil winding during successive steps of assembly.

Fig. 4 illustrates binding strips or tapes to secure the terminals from or ends of the conductor constituting the coil of Figs. 1 to 3.

Fig. 5 is a perspective View of the component parts of core structure on which the coil of Figs. 1 to 3 is mounted.

Figs. 6 and 7 are views of a transformer utilizing the above coil and are structures in final stages of assembly.

Upon a form 1 of desired cross sectional dimensions and configuration and of suitable material, as for example, fibre, is wound acoil A of copper wire, insulated, for example, by a coating of enamel. The ends 2, 2 of the coil conductor constitute the terminals of or taps from the winding. The coil is suitably insulated, as by a layer or strip of varnished cambric, oiled silk or the equivalent, from a second coil superimposed thereon and having terminals 3, 3 constituting ends of the conductor of the second winding. Upon one or more layers 1928. Serial No. 280,371.

of insulating fabric or equivalent enclosing the second windin is wound a third coil G of relatively fine wire. The ends of or taps from the coil are suitably secured, as by soldering, to metal foil strips 4, 4 which extend exteriorly of the coil. The composite winding is covered with a layer 5 of insulating fabric to protect the windings from mechanical and electrical damage, and if necessary or desirable layers of similar material may be interposed between adjacent layers' of any or all of the coils. The extensions or ends 2, 2 and 3, 3 of the first and second coils A and B, are flattened or otherwise deformed as by a punch press operation, to fracture the enamel or other inslulating coating, as cotton or silk, and to separate it or greatly facilitate its removal from the wire. The ends are then bent over-the ends of the coil and substantially into contact with the outside thereof. The metal foil terminals 4 of the third coil, being already free of insulating material and flat, are merely bent over the coil assembly as indicated. The extremities of the leads 2 are passed through spaced apertures 6, 6 in a thin flexible strip 7 of suitable insulating material, as varnished or oiled fabric, which may be coated with a suitable adhesive as, for example, shellac or the like, and the coated surface pressed into contact with the covering 5 of the coil assembly. To maintain the strip 7 in place there may be additionally provided a strip of tape 8 which is in adhesive contact with layer 5 of the coil and intermediate the ends firmly presses against the tips of the terminals 2, preventing them from springing outwardly and loosening the strip 7.

Similarly the strip 9 having pairs of apertures 10 through which are passed the terminals 3, 3, as indicated in Fig. 3, is secured to the coil by suitable adhesive material and additionally bound by a tape 11. The strip 9 is also provided with slots 10, preferably narrower than, and adapted to overlie terminals 4, 4.

The coil assembly as shown in Fig. 3, may then be placed in a vacuum chamber an impregnated with a suitable insulating compound, as for example, a' mixture com prising resin, or equivalent, and Wax, such as bees-wax, paraflin wax, etc. During this operation the leads 2, 2 3, 3 and the terminals 4, 4 of the several windings of the coil are immersed in the impregnating compound and are subjected to the action of its resin or equivalent component. Upon removal of the coil from the chamber, the flexible leads 12, preferably of different colors or markings, may be soldered to the coil ends or terminals, the resin component of the impregnating mixture serving as a soldering flux. Additionally, the soldering is facili tated by the flattening of the wire ends as the available surface with which the solder and the soldering tool may, make contact is increased. Further, the hot solder is easily retained by the plane surface whereas it is difficult to prevent it from rolling off a' round wire.

Hithertofore it has been the practice laboriously to scrape or dissolve the enamel or other insulation from the ends of the coil, apply a soldering flux thereto and then perform the diflicult operation of soldering .to the round wire, which difficulty was increased when the wire was of relatively large diameter. Furthermore, it was often necessary to perform the preliminary operation of tinning the leads.

The ends of the wire of the third coil C are not flattened because it is to. small and in any event the area of the flattened surface would not be suitably large to attach a lead thereto. It is necessary in this instance to use the metal foil strips or e'xtensions 4 as in the prior practice with large wires, prior to this invention.

The exposed portions of the flat terminals to which the flexible leads 12 are connected are intermediate the anchored extremities of the terminals and the points where they enter the winding proper. Any strain or pull upon the leads 12 during further assembly or installation is not transferred wholly to or is not effective to produce movement of the terminals to break the conductor comprising them or to unwind or otherwise affect the coil winding. The solder holding leads to terminals 4, 4 forms a key closely fitting in the apertures 10, 10, preventing movement of the terminals in any direction.

It is preferable, however, particularly when the coil is to be used as a transformer winding, that prior to the impregnation of the coil, it be mounted upon an associated core structure. Referring to Fig. 5, the core may comprise two major portions 13 and 14, each consisting of a stack of substantially E-shapcd laminations. As shown,'each of the transformer legs comprises opposite extensions of members 13 and ll having, respectively, a tongue portion 15 and a groove 16. The coil assembly is disposed on the middle leg 17 of one of the transformer core portions 13 and 14, whereupon the other portion is associated therewith to form the transformer in substantially its assembled state. Clips 18 comprising substantially U- shaped metal members, preferably of iron or steel and having a curved or lip portion at the open end of the U, are forced over the outside legs of theassembledcoreintheregion of overlap of the component portions 13 and 14: thereof to retain the laminations in their proper position. One or more wedge shaped members 19, preferably of suitable insulating material, may then be forced between the coil form 1 and the middle leg 17 of the transformer core to retain the coil firmly in place thereon, and to form an additional means for clamping the laminations together at points distant from those at 18.

The coil and core assembly is then impregnated as above described, the impregnating material filling in spaces between the laminations and preventing humming due to their vibration when excited by an alternating current. Thereafter the leads 12 may be soldered to the coil terminals as above described. The entire assembly may then be disposed in a suitable container into which a suitable moisture-proof compound is poured to protect the entire structure from the atmosphere.

It will be understood that the sequence of steps may be varied without departing from my invention, for example, the leads 12 may be soldered to the terminals before, during, or after anchoring of the terminal extremities to theoutside of the coil winding; the winding may at any stage be mounted on its core and the subsequent steps of assembly then completed.

For brevity in the appended claims the term resin or resinous mixture, is employed to comprehend rosin or resin of the type which will facilitate or act as a flux in soldering, and any equivalent material which will facilitate or act as a flux in soldering and constituting a component of or contained in the impregnating material.

What I claim is: I

1. In the art of constructing coil windings of insulated conductor, a method which comprises deforming the cross-section of ends of the conductor constituting terminals of the winding to free them of insulation, coating the deformed ends during impregnation of the coil with a resinous mixture, and soldering leads to the ends or terminals utilizing said coating as a fluxing agent.

2. In the art of constructing coil windings for electrical apparatus, a method which comprises securing bare terminals of said winding to the exterior thereof, simultaneously impregnating the coil and coating said terminals with a resinous mixture, and soldering leads'to said terminals utilizing the coating as a fluxing agent.

3. In the art of constructing coil windings of insulated conductor, a method which comprises flattening ends of the conductor constituting terminals of the coil to free them of insulation, simultaneously impregnating the coil and coating said flattened ends with a resinous mixture, and soldering leads to the terminals ultilizing the coating as a fluxing agent.

v4. In the art of constructing coil windings of enamel coated conductor, a method which comprises flattening ends of the conductor constituting terminals of the coil to remove the enamel coating, simultaneously impregnating the coil and coating the flattened, bared ends with a resinous mixture, and soldering leads to the terminals ultilizing the coating as a fluxing agent.

5,. In the art of constructing coil windings of insulated conductor, a method which comprises flattening ends of the conductor constituting terminals of the coil to free them of insulation, binding the flattened ends to the exterior of the winding, simultaneously impregnating the coil and coating exposed portions of said flattened ends w th a resinous mixture, and solder ng leads to the terminals utilizing the coating as a fluxing agent.

6. In the art of constructing electro-magnetic apparatus, a method which comprises mounting a wound coil upon laminated core structure, simultaneously impregnating the coil and core assembly and coating bare terminals of the coil with a resinous mixture, and soldering leads to the terminals utilizing the coating as a fluxing agent.

7. A coil winding for electrical apparatus having a strip of insulating fabric disposed on the exterior of said coil winding, and a. binding strip adhesively secured thereto and maintaining terminals of said coil in spaced relation thereagainst.

8. A coil windin for electrical apparatus having a flexible inding strip of insulation in engagement with the exterior surface of said coil and having spaced apertures receiving the ends of flat terminals of said coil, and flexible leads secured to exposed portions of said flat terminals.

9. A coil winding for electrical apparatus having a strip of fabric having spaced apertures receiving ends of flat terminals of thereon, strips of insulation having spaced apertures receiving terminals of said coils, means to retain said strip against the extenor of said windings, and flexible leads soldered to said terminals intermediate their ends and of entry into said winding.

11. In the art of manufacture of coils, a method which comprises winding a conductor into coil form, securing terminals of the winding to the exterior of the coil, immersing the coil with terminals of its conductor exposed in impregnating material containing a material which facilitates soldering, and after impregnation soldering a conductor to said terminal.

12. In the art of manufacture of coils, a method which comprises securing a bare flat terminal of a winding to the exterior thereof with a flexible strip of insulation having an aperture overlying the terminal, and soldering leads to the terminal portion exposed through said aperture to effect electrical connection with said coil and to prevent displacement of said terminal thereof.

13. -A coil Winding for electrical appara tus having a strip of flexible insulating ma terial in intimate engagement with the exterior surface of said coil, and terminal extensions for said coil disposed between said strip and the exterior surface of said coil,

said strip having apertures exposing said terminal extensions and co-operatin therewith to prevent displacement thereoi 14. A coil winding for electrical apparatus comprising a strip of fabric havin spaced apertures co-operating with a terminal of the coil to hold at least the end thereof against the exterior of the coil, and to expose a portion intermediate the end and point of enta' into said winding, and a lead soldefed to e exposed portion of said termma 7 ROBERT C. DACOSTA. 

